Field of the Invention
The present invention relates to an image processing apparatus and an image processing method.
Description of the Related Art
In imaging diagnosis using a medical image (three-dimensional tomographic image representing information about the inside of an object), a doctor performs diagnosis while comparing images captured by a plurality of imaging apparatuses (modalities) in different body postures at different times with imaging parameters, and the like. Since postures and shapes of an object differ between images, identification of a lesion area and comparison are difficult. Thus, alignment between a plurality of images is attempted. Conversion and deformation of the posture can be performed on one image to generate an image coincident with the other image.
However, the result of general alignment contains an error and is not always accurate. The doctor therefore cannot determine how reliable the alignment result is.
As a method of estimating an alignment error, Japanese Patent Laid-Open No. 2013-198722 discloses a method based on the instability (ambiguity of the solution) of a deformation parameter estimated as the result of deformation alignment. Based on the variation range of the estimated position of a point corresponding to a point of interest upon intentionally varying an unstable parameter, the method in Japanese Patent Laid-Open No. 2013-198722 estimates the error of the estimated position.
However, the error estimation method described in Japanese Patent Laid-Open No. 2013-198722 cannot consider a factor other than the instability of the estimated parameter.
The present invention provides a technique for providing a method of obtaining an estimation error or reliability in alignment (especially alignment arising from interpolation) between a plurality of images.